Investigators Leave Charlotte Crash Scene, Though Work Far From Over

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CHARLOTTE, N.C. — Field investigators packed up
debris and headed home Sunday for more detective work into the
cause of a fatal commuter airline crash that killed all 21 people
aboard.

US Airways Express Flight 5481 crashed 37 seconds into its
flight Wednesday, preliminary data show. A final conclusion about
what happened could take months or even years after investigators
finish reviewing maintenance records, testing the charred debris
and running computer simulations.

In four days, investigators looked at factors such as the
plane's weight and balance, recent maintenance and whether a larger
jet could have buffeted it with enough turbulence to cause the
crash.

They scrutinized a West Virginia facility that serviced the
aircraft Monday night and interviewed baggage handlers about a
pre-takeoff discussion of how much baggage could go on board.

The crash team from the National Transportation Safety Board
will ship some key parts to Washington, D.C., where technicians in
the board's materials lab can examine metal parts for cracks with
microscopes, X-ray machines and ultrasound equipment, said Bill
Waldock, an aeronautical science professor in Prescott, Ariz., who
has assisted in NTSB probes.

Often in a crash, two pieces of metal bang together and leave a
scar known as a "witness mark," he said. From these marks,
investigators could tell the position of the plane's elevator and
horizontal stabilizer at the time of impact.

Technicians will analyze the cockpit voice and flight data
recorders. Inside the so-called "black boxes" are memory modules,
either on tape or computer chips.

Investigators can do a sound spectrum analysis of the voice
recorder, searching for vibrations and other noises, Waldock said.

They will plot the plane's actions from the flight data
recorder, which will then be matched with the cockpit voice
recording.

"That gives investigators a good picture of what transpired
during the flight, and what kind of action and reaction the crew
took," said Greg Feith, a former senior NTSB air safety
investigator who led the probe of a 1994 USAir crash in Charlotte
that killed 37 people.

The engines will be sent to the manufacturer's facility in
Canada, where NTSB investigators will take them apart.

After about six to nine months, the NTSB probe will lead to a
collection of the facts, without any analysis.

Then investigators will analyze that data and compile a draft of
the final report, which takes another six to nine months. If the
agency finds problems needing immediate attention, the NTSB will
issue emergency recommendations.

The initial report, which includes a probable cause,
recommendations and any other conclusions, is then reviewed by the
safety board in a public meeting. The board will discuss the report
and vote on the findings.

Probing the Alaska Airlines crash off the coast of California
took almost three years, ending just last month.

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